Bird Strike - if you've bought IT equipment for any length of time, you should have realised that you can only ever buy seperately the bits that DON'T wear out.
When your keyboard wears out you will have two choices:
1. Hunt high and low for an identical set of what you have already bought, for which you will have to pay a premium becuase it is now rare.
2. Buy the item that replaced what you have bought in the manufacturers inventory, which will be better and so cost more, but be incompatible with what you have.
Heads they win, Tails you lose.